It has been well known for many years to propagate seeds, seedlings and cuttings for fruit and vegetable crops in growth substrates formed from mineral wool. Once the plants have rooted and developed leaves in a first growth substrate, they are usually transferred to a second growth substrate.
It is conventional for the growing process to be started at a propagator's facility and then the propagator transfers the plants at an appropriate stage to a grower's facility where the growing process is completed and the crop harvested.
Currently vegetable plants are normally propagated in a first growth substrate which is relatively small in volume (a plug) and then transferred to a larger second growth substrate (a block) and grown for a further period, after which they can then be transferred to the grower, where the second growth substrates are positioned on slabs of growth substrate for further growth.
The dimensions of the essentially cylindrical plug have traditionally been around height 2.5 cm, diameter 2 cm. The dimensions of the block have traditionally been around width 10 cm, length 10 cm, height 6.5 cm. The dimensions of the slabs vary according to the crop being grown but usually have height 7.5 cm.
They are normally at least 100 cm in length and at least 12 cm in width.
The current system means that the propagator is responsible for the plants for around 4 to 9 weeks (depending on crop type and time of year) and then the grower is responsible for them for a considerable period of weeks before a harvestable crop is generated. The grower then has to supply energy, water, nutrients, etc for all of this time. In practice, this means that a grower often does not make any profit from crops during this first stage. The long period of time for which the grower is responsible for the plants before a harvestable crop is generated also means that it is more difficult for the grower to time a crop to match specific times of year when the relevant crop is particularly required.
This traditional system has been used for many years for propagating and growing fruits and vegetables throughout the growing industry, in essentially the same form, despite these disadvantages.
It would be desirable to provide a growing method which allows ultimately better root and shoot development and hence a better quality of vegetable crop and which can also lead to a harvestable crop in a shorter period of time.
Particular problems arise when a growth substrate is to be used for propagation. For optimum propagation of the plants being grown, propagators would ideally like to supply water frequently to the substrate. Unfortunately, this has a problem that the growth substrate then becomes too wet and this has a negative effect on the growth of the plants, especially because in periods of low light intensity it can result in a high risk of disease.
Accordingly, it would be desirable to provide a propagation and growing method which alleviates these disadvantages.
NL8502065 describes a traditional growing system, corresponding to that described above, in which small plugs (dimensions 2.5 cm high and 2 cm in diameter) are used for germination of seedlings. The dimensions of the plug are chosen to enable automated sowing by machine during propagation and its density is chosen to be in the range 60 to 90 kg/m3 so as to allow penetration of the first roots into the plug material. After germination, the plug is positioned in a cut-out in a block for further growth of the seedling and then after further cultivation the block can be positioned on a mat for further growth of the plant. The dimensions of the block are not discussed.